The field of the invention is inhibition of growth of the pathogen Helicobacter pylori.
Helicobacter pylori is a microaerophilic Gram-negative bacterium implicated in several upper gastrointestinal human illnesses including gastritis, duodenal ulcer, and gastric carcinoma (Eurogast Study Group, (1993) Lancet, 341:1359-62; Talley et al., (1991) J. Natl. Cancer Inst. 83:1734-9; Wee et al., (1992) Gut 33:1029-32). There are several methods known for culturing this agent in relatively low volumes of 100 ml to 1 L (Hudson, (1989) In: Gastroduodenal Pathology and Campylobacter pylori, Megraud and Lamouliane (eds.), p. 11, Elsevier; Millar, (1992) Antimicrobial Agents and Chemotherapy 36:185-7; Secker et al., (1991) J. Clin. Micro. 29:1060-1; Xia et al., (1993) J. Clin. Pathol. 46:750-3).
High volume airflow and agitation required for adequate gas exchange in large volume fermenters create the potential problem of foaming. Foaming is controlled with antifoams added to the culture medium; these typically consist of highly insoluble silicon polymers which are made miscible in water by emulsifying surfactants and/or non-ionic detergents. Simethicone (polydimethylsiloxane) is the silicone polymer used in many commercial antifoams. Antifoams are widely used in the pharmaceutical and biotechnology industries. They are also marketed for relief of intestinal gas, or included in antacids for the same purpose.
Although Helicobacter pylori is microaerophilic, successful culture requires stirring and aeration (Goodwin et al., (1986) J. Antimicro. Chemother. 7:309-14; Morgan et al., (1987) J. Clin. Micro. 25:2123-5; Shadowen et al., (1989) J. Clin. Micro 27:1744-7). We found that despite use of conditions reported for large scale liquid culture (Olivieri et al. (J. Clin. Micro. 31:160-2), our 5-20 L fermenter batches did not grow.